With recent development of wireless communication techniques including WirelessLAN, it is being promoted to replace a part of a communication system using wired communication with a wireless communication system in home or office environments. For example, instead of connecting a notebook computer to a wired LAN network to perform communication by connecting a network cable with the notebook computer to connect to the network, connection may be made to a network via an access point with the use of WirelessLAN. As another example, instead of printing an image taken by a digital camera with a printer by connecting the digital camera and the printer via a USB cable or the like to transfer the image, the image may be transferred to the printer with the use of Bluetooth or WirelessLAN.
In addition to the purpose of replacing wired communication, there is great expectation for a close range wireless communication mode such as NFC (Near Field Communication). It is possible to perform communication between pieces of equipment provided with NFC only by bringing the pieces of equipment close to each other. Therefore, NFC has gotten attention as such as can provide a user with convenient means for easily utilizing various services in performing settlement processing, processing for accessing to services or the like.
From the above situation, it is anticipated that wireless communication such as WirelessLAN and NFC will further spread. That is, it is anticipated that, not only in homes and offices but also in every environment, a scene will be more often seen that various pieces of equipment provided with the above-described wireless communication mode perform communication so that a user can utilize various services.
In the case where many pieces of equipment can perform wireless communication as described above, it is essential to certainly grasp what kinds of equipment are connected to each network and perform authentication processing to avoid improper connection or connection from malicious equipment. For example, in a home environment, it must be avoided to wrongly connect to a printer of the next house when an image taken by a digital camera is printed. In an office environment, it is necessary to certainly perform authentication processing in connecting to an access point in order to prevent a malicious third person from invading an intranet.
For example, in IEEE 802.11, an authentication method utilizing a common key cryptography or an authentication method utilizing an authentication server such as RADIUS is used for such authentication processing. In Bluetooth, access control is performed by inputting a password such as a PIN code.
As described above, in an environment where wireless communication is widely and generally spread, it is necessary to prevent improper connection or invalid access by certainly performing authentication processing.
However, if consideration is given to authentication processing to be performed when portable terminals, such as a digital camera and a mobile printer provided with a wireless communication function, communicate with each other, the authentication methods described above are not necessarily suitable. For example, in general, a portable terminal does not have sufficient input means for authentication or is not provided with such input means at all. Accordingly, even if a user attempts authentication by inputting a password in such an environment, it may be very troublesome for the user to input the password, or input itself may be impossible. It is also impossible to use the method utilizing an authentication server in such an ad-hoc environment where a network is constituted only by terminals to perform communication, because there is not an authentication server on the network. Furthermore, it is also impossible for the method utilizing a common key cryptography to completely prevent access from those other than an authorized user, because security in key exchange is not specifically provided and, therefore, there is a possibility that a key may be obtained by a third person intentionally or by mistake.
In Japanese Patent Laid-Open No. 2001-189722 and in Japanese Patent Laid-Open No. 2003-174468, there is proposed an authentication system utilizing a card.
However, in such a system, it is possible for a third person to acquire information for authentication from each equipment by using an apparatus provided with a data reading/writing function equivalent to that of the card. Therefore, the system also cannot enable satisfactory security to be obtained.